Need ideas chasing my tail

2DaDarkZide PR

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Hello fellas, its been a while.

To the point, I have an 06 GT, stock, 107k. I bought it in January with 96k, Manual.

I have gotten to the point where I can replicate the issue almost at will. The engine will begin to run TERRIBLY, almost as if half the cylinders dropped. No codes, not once between 96k to 107k. I can get the engine to run and idle just fine again by revving it up.

It only happens upon coming to a stop from a long run, say, my 30 miles and then off the exit each way to home or work. Or, pulling into places slowly like say, parking lots, driveway inclines, etc. The RPM would drop to barely sustaining idle and and shake and knock like crazy. If I hit the gas it will putter and knock until say 2k-2500 RPM then it revs up normally, so I let the gas go and it runs fine again.

I have replaced, Fuel filter, Spark plugs, Coils, and lastly yesterday, Fuel injectors. All with OEM stuff. I have yet to attempt to modify or race the vehicle since I got it because although it runs great most of the time, I don't want to risk it.

It has never stalled or thrown a code, not once. I had some missing power and lag but switching the injectors solved that instantly, so that was its own separate issue.

Again, if I am in 1st gear and slowly revving and slipping the clutch as you would to enter somewhere slowly, that is when almost ALWAYS it happens. Not sure what else to check? VCT solenoids? Chain Tensioners? Timing chain itself? I say these because when its idling all crazy for those few seconds it sounds almost as if the chain were super loose and rattling but cant be sure.
 

GlassTop09

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Hello fellas, its been a while.

To the point, I have an 06 GT, stock, 107k. I bought it in January with 96k, Manual.

I have gotten to the point where I can replicate the issue almost at will. The engine will begin to run TERRIBLY, almost as if half the cylinders dropped. No codes, not once between 96k to 107k. I can get the engine to run and idle just fine again by revving it up.

It only happens upon coming to a stop from a long run, say, my 30 miles and then off the exit each way to home or work. Or, pulling into places slowly like say, parking lots, driveway inclines, etc. The RPM would drop to barely sustaining idle and and shake and knock like crazy. If I hit the gas it will putter and knock until say 2k-2500 RPM then it revs up normally, so I let the gas go and it runs fine again.

I have replaced, Fuel filter, Spark plugs, Coils, and lastly yesterday, Fuel injectors. All with OEM stuff. I have yet to attempt to modify or race the vehicle since I got it because although it runs great most of the time, I don't want to risk it.

It has never stalled or thrown a code, not once. I had some missing power and lag but switching the injectors solved that instantly, so that was its own separate issue.

Again, if I am in 1st gear and slowly revving and slipping the clutch as you would to enter somewhere slowly, that is when almost ALWAYS it happens. Not sure what else to check? VCT solenoids? Chain Tensioners? Timing chain itself? I say these because when its idling all crazy for those few seconds it sounds almost as if the chain were super loose and rattling but cant be sure.

If you haven't already, next time try doing what you've done to replicate this issue, but w\ both VCT solenoids unplugged (this puts the VCT solenoids in their neutral position to hold the cam phasers at base cam timing 0*). If all clears up from this test you've then verified that at least 1 of the VCT solenoids (most likely it's the VCT solenoid on B1--passenger side but could be the 1 on B2--driver side as well) is sticking which is throwing the cams out of phase timing wise which will throw engine power balance out of phase causing the engine shake, knocking sounds (but nothing is striking anything as long as the engine timing chains & cam phasers haven't jumped time...full VCT compliant cams can be retarded as much as 60* by design w\o piston to valve interference issues) then once you open throttle enough for the PCM to change the PWM control signal output enough to the stuck VCT solenoid to free the plunger to bring the cams back into phase then all corrects itself. If the issue remains after doing this test then this is leaning towards the cam phasers being suspect in concert w\ the VCT solenoids.

But before you go do all this, IMHO you really need to run an engine oil pressure check w\ engine at hot idle to verify\ensure that there is sufficient oil pressure (thus oil volume) to properly actuate the VCT system....and you can't go by the oil pressure gauge in the IC cluster (not a real pressure gauge). You'll have to remove the oil pressure sending switch behind the oil filter & install a mechanical pressure gauge to read the actual engine oil pressure. The passenger side (bank 1) is usually the 1st side for these issues to occur as it is at the end of the oil pressure\volume flow routing thru the engine. I think the original min spec is 26 psi but Ford revised this later to 18-20 psi for proper VCT operation (got this from FordTechMakuloco's YouTube videos for 5.4L 3V Triton but 4.6L 3V is similar design) but the min spec as read from my Chilton manual for the 4.6L V8 is 75 psi @ 2,000 RPM's which doesn't mean anything at idle\off idle RPM's (where your issue is occurring) but is the spec that is obtained from Ford by Chilton for the 4.6L 3V engine.

I say this as the VCT solenoid unplugging test I mentioned is the easy stuff to do, but the proper testing process to perform for any suspected VCT issues should always start w\ an engine oil pressure check to verify this is good before going on further cause if the engine oil pressure is too low out of spec then the rest doesn't matter as this will need to be addressed promptly & to address it you'll have to do a full engine timing job anyway (chains, cam phasers, guides, tensioners, crank sprocket, crank tone wheel, VCT solenoids) as all this will need to be removed to gain access to the oil pump.

Note I typed the word "should"...….. I realize that most DIY'ers (including myself as well) will probably go the easy route 1st when diagnosing stuff like this so just keep this in mind as w\o sufficient oil pressure\volume available the VCT system ain't gonna operate correctly anyway (the cams will momentarily go out of phase under initial acceleration until the B1 oil pressure\volume catches up to B2 (B2 gets the oil pressure\volume 1st after filtration) causing similar issues as you're experiencing now.

Hope this helps.
 
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2DaDarkZide PR

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If you haven't already, next time try doing what you've done to replicate this issue, but w\ both VCT solenoids unplugged (this puts the VCT solenoids in their neutral position to hold the cam phasers at base cam timing 0*). If all clears up from this test you've then verified that at least 1 of the VCT solenoids (most likely it's the VCT solenoid on B1--passenger side but could be the 1 on B2--driver side as well) is sticking which is throwing the cams out of phase timing wise which will throw engine power balance out of phase causing the engine shake, knocking sounds (but nothing is striking anything as long as the engine timing chains & cam phasers haven't jumped time...full VCT compliant cams can be retarded as much as 60* by design w\o piston to valve interference issues) then once you open throttle enough for the PCM to change the PWM control signal output enough to the stuck VCT solenoid to free the plunger to bring the cams back into phase then all corrects itself. If the issue remains after doing this test then this is leaning towards the cam phasers being suspect in concert w\ the VCT solenoids.

But before you go do all this, IMHO you really need to run an engine oil pressure check w\ engine at hot idle to verify\ensure that there is sufficient oil pressure (thus oil volume) to properly actuate the VCT system....and you can't go by the oil pressure gauge in the IC cluster (not a real pressure gauge). You'll have to remove the oil pressure sending switch behind the oil filter & install a mechanical pressure gauge to read the actual engine oil pressure. The passenger side (bank 1) is usually the 1st side for these issues to occur as it is at the end of the oil pressure\volume flow routing thru the engine. I think the original min spec is 26 psi but Ford revised this later to 18-20 psi for proper VCT operation (got this from FordTechMakuloco's YouTube videos for 5.4L 3V Triton but 4.6L 3V is similar design) but the min spec as read from my Chilton manual for the 4.6L V8 is 75 psi @ 2,000 RPM's which doesn't mean anything at idle\off idle RPM's (where your issue is occurring) but is the spec that is obtained from Ford by Chilton for the 4.6L 3V engine.

I say this as the VCT solenoid unplugging test I mentioned is the easy stuff to do, but the proper testing process to perform for any suspected VCT issues should always start w\ an engine oil pressure check to verify this is good before going on further cause if the engine oil pressure is too low out of spec then the rest doesn't matter as this will need to be addressed promptly & to address it you'll have to do a full engine timing job anyway (chains, cam phasers, guides, tensioners, crank sprocket, crank tone wheel, VCT solenoids) as all this will need to be removed to gain access to the oil pump.

Note I typed the word "should"...….. I realize that most DIY'ers (including myself as well) will probably go the easy route 1st when diagnosing stuff like this so just keep this in mind as w\o sufficient oil pressure\volume available the VCT system ain't gonna operate correctly anyway (the cams will momentarily go out of phase under initial acceleration until the B1 oil pressure\volume catches up to B2 (B2 gets the oil pressure\volume 1st after filtration) causing similar issues as you're experiencing now.

Hope this helps.

I was suspecting mail an oil pressure issue but since I’m in the process of buying a 2nd car so I can do the full timing job, simultaneously with cams and upgraded oil gears, comfortably and safely, I’ll try what you said first. May very well be B1 because the engine when idling correctly has a much Louder tap on the passenger side. With the screw driver to ear method I can hear and feel it versus the driver side.

Thanks for your insight, kind sir


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drive_55_not

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Some 05/06 cars had issues with fuel cavitation, the symptoms sound exactly what you are experiencing.

TSB 06-9-9 was issued that replaced the pump.


.
 

2DaDarkZide PR

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Some 05/06 cars had issues with fuel cavitation, the symptoms sound exactly what you are experiencing.

TSB 06-9-9 was issued that replaced the pump.


.

Thanks for typing that because for some reason I forgot to mention a symptom. The car will randomly fuel cut like if I hit the limiter. Often when leaving a stop. I’ll start to take off in 1st and the car will completely and abruptly cut them immediately resume.

Also when I’m on the highway and I want to downshift and rip it, it occasionally cuts fuel prior to resuming the acceleration while driving at highway speeds.

These 2 details, seem more related to what you stated about the TSB, but I have a feeling I have ALL the above issues. I literally have every Other issue these cars have lol.

(Shifter falling apart, door Panel leather trashed, autoup only works on passenger, RPM stepper motor going berserk)


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drive_55_not

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The fuel pump is pretty easy to R&R, Just get a new hat gasket as the old one will swell and expand making it impossible to reinstall ..


.
 

2DaDarkZide PR

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The fuel pump is pretty easy to R&R, Just get a new hat gasket as the old one will swell and expand making it impossible to reinstall ..


.
Yes, thanks. I’ve upgraded the fuel pump in 2 prior S197.

Mo money, Mo money, Mo Money


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08MustangDude

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When is the last time the fuel FILTER was changed? Ford recommends every 15,000
miles... Very easy to do. A clogged filter will slow fuel delivery... Can't hurt for
how cheap and easy it is to replace.
 

Charly

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Hello fellas, its been a while.

To the point, I have an 06 GT, stock, 107k. I bought it in January with 96k, Manual.

I have gotten to the point where I can replicate the issue almost at will. The engine will begin to run TERRIBLY, almost as if half the cylinders dropped. No codes, not once between 96k to 107k. I can get the engine to run and idle just fine again by revving it up.

It only happens upon coming to a stop from a long run, say, my 30 miles and then off the exit each way to home or work. Or, pulling into places slowly like say, parking lots, driveway inclines, etc. The RPM would drop to barely sustaining idle and and shake and knock like crazy. If I hit the gas it will putter and knock until say 2k-2500 RPM then it revs up normally, so I let the gas go and it runs fine again.

I have replaced, Fuel filter, Spark plugs, Coils, and lastly yesterday, Fuel injectors. All with OEM stuff. I have yet to attempt to modify or race the vehicle since I got it because although it runs great most of the time, I don't want to risk it.

It has never stalled or thrown a code, not once. I had some missing power and lag but switching the injectors solved that instantly, so that was its own separate issue.

Again, if I am in 1st gear and slowly revving and slipping the clutch as you would to enter somewhere slowly, that is when almost ALWAYS it happens. Not sure what else to check? VCT solenoids? Chain Tensioners? Timing chain itself? I say these because when its idling all crazy for those few seconds it sounds almost as if the chain were super loose and rattling but cant be sure.


I recently purchased an 07 GT and had a similar problem, of course I replaced spark plugs, which help improve problem, then I replaced the fuel rail pressure temperature sensor, which has drastically improved the idle and overall response. The cost of the part is minimal. The car has performance cams and long headers with Flow Master exhaust. 75K miles on car.
 

07 Boss

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It might be a stretch but I look for simple solutions. Do you have a stock pvc system? Do you have stock charge motion plates? Those tend to get pretty gnarly with oil and gunk. Butterflies could be sticking or not operating properly. It may cause some of the symptoms you're describing.

As far as the fuel pump TSB, I've helped a couple of folks out with that one and you symptoms don't quite match up. This usually happens after long sustained cruising at a constant speed. Not saying it's not but it just doesn't feel right to me.
 

2DaDarkZide PR

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When is the last time the fuel FILTER was changed? Ford recommends every 15,000
miles... Very easy to do. A clogged filter will slow fuel delivery... Can't hurt for
how cheap and easy it is to replace.
I mentioned that in the OP. Thanks. :)


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2DaDarkZide PR

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It might be a stretch but I look for simple solutions. Do you have a stock pvc system? Do you have stock charge motion plates? Those tend to get pretty gnarly with oil and gunk. Butterflies could be sticking or not operating properly. It may cause some of the symptoms you're describing.

As far as the fuel pump TSB, I've helped a couple of folks out with that one and you symptoms don't quite match up. This usually happens after long sustained cruising at a constant speed. Not saying it's not but it just doesn't feel right to me.

The long sustained cruise is exactly when it happens.

I have a feeling the car just needs complete maintenance.

Everything I’ve replaced has been noticeably shot, worn or beat. Charge Motion I’m checking next and VCT. In the end the entire engine will be refreshed almost haha


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